<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>FileTest</title>
    <style>
        input {
            margin: 10px;
            outline: none;
        }
        button {
            margin: 10px;
            width: 200px;
            height: 50px;
        }
    </style>
</head>
<body>
    <form
        action="/upload"
        method="post"
        enctype="multipart/form-data"
    >
        name: <input type="text" name="username"><br>
        age: <input type="text" name="age"><br>
        avatar: <input type="file" name="avatar"><br>
        <button type="submit">submit</button>
    </form>
</body>
</html>